mc-to-discord.bash

#!/usr/bin/env bash
shopt -s extglob

: ${WEBHOOK:?Requires envvar WEBHOOK}
for C in jq curl; do
	if command -v "$C" > /dev/null; then
		echo "Requires $C to be installed"
		exit 1
	fi
done

RE_USER='[[:alnum:]_-]*'
: '[[:xdigit:]]'
RE_UUID="$_{8}-$_{4}-$_{4}-$_{4}-$_{12}"

DEFAULT_UUID=870aba9340e848b389c532ece00d6630

declare -A UUIDS=

while read -r; do
	if ! [[ $REPLY =~ ^'['.*?'] ['.*?'] [minecraft/'(.*?)']: '(.*)$ ]]; then
		continue
	fi
	VIA="${BASH_REMATCH[1]}"
	MSG="${BASH_REMATCH[2]}"
	if [ ]; then : ;
	# Authentication stuff
	elif [[ $VIA = 'ServerLoginNetHandler' ]]; then
		# UUID notice
		if [[ $MSG =~ ^'UUID of player '($RE_USER)' is '($RE_UUID)$ ]]; then
			UUIDS[${BASH_REMATCH[1]}]=${BASH_REMATCH[2]}
		fi
	# General messages
	elif [[ $VIA = 'DedicatedServer' ]]; then
		if [ ]; then : ;
		# Join
		elif [[ $MSG =~ ^($RE_USER)' joined the game'$ ]]; then
			jq -nc \
				--arg USERNAME "${BASH_REMATCH[1]}" \
				--arg UUID "${UUIDS[${BASH_REMATCH[1]}]:-$DEFAULT_UUID}" \
				'{ "content": "**\($USERNAME)** joined the game" }'
		# Part
		elif [[ $MSG =~ ^($RE_USER)' left the game'$ ]]; then
			jq -nc \
				--arg USERNAME "${BASH_REMATCH[1]}" \
				--arg UUID "${UUIDS[${BASH_REMATCH[1]}]:-$DEFAULT_UUID}" \
				'{ "content": "**\($USERNAME)** left the game" }'
		# User Message
		elif [[ $MSG =~ ^'<'($RE_USER)'> '(.*)$ ]]; then
			jq -nc \
				--arg USERNAME "${BASH_REMATCH[1]}" \
				--arg UUID "${UUIDS[${BASH_REMATCH[1]}]:-$DEFAULT_UUID}" \
				--arg MESSAGE "${BASH_REMATCH[2]}" \
				'{
					"content": $MESSAGE,
					"username": $USERNAME,
					"avatar_url": "https://crafatar.com/renders/head/\($UUID)?scale=10"
				}'
		# User Action
		elif [[ $MSG =~ ^'* '($RE_USER)' '(.*)$ ]]; then
			jq -nc \
				--arg USERNAME "${BASH_REMATCH[1]}" \
				--arg UUID "${UUIDS[${BASH_REMATCH[1]}]:-$DEFAULT_UUID}" \
				--arg MESSAGE "${BASH_REMATCH[2]}" \
				'{
					"content": "_\($MESSAGE)_",
					"username": $USERNAME,
					"avatar_url": "https://crafatar.com/renders/head/\($UUID)?scale=10"
				}'
		fi
	fi
done |
while read -r; do
    curl -sS -H "Content-Type: application/json" -d @- "$WEBHOOK" <<< $REPLY
done